A class action suit was filed Wednesday against 10 of the world's biggest auto manufacturers for allegedly concealing the risk of carbon monoxide poisoning in keyless ignition systems.

28 U.S. consumers filed the complaint in Los Angeles federal court, claiming that the automakers concealed the possibility of carbon monoxide due to keyless ignition systems in more than 5 million cars. It allegedly led to 13 deaths.  

Keyless ignition systems let drivers start the car by pressing a button as they put an electronic "key fob" in their pockets or purse. If the key fob is not detected, the car will not start. The defect is that even if the fob is no longer in the car, it will continue to run.

Cars that were left running in enclosed garage by their unsuspecting drivers caused a build-up of toxic carbon monoxide gas that penetrated the homes. This mistake can be very deadly.

The suit seeks to order the car manufacturers involved to install an automatic shutdown system on the affected cars. The lawsuit also seeks compensatory damages, as well as punitive damages.

The class suit is against Toyota, Honda, Ford, Nissan, Volkswagen, BMW, Mercedes-Benz, Bentley, Kia, and Hyundai.

According to one complainant, the automakers had actual knowledge of the dangers behind keyless fobs leading to carbon monoxide poisoning.

The Centers for Disease Control and Prevention reported 430 deaths a year due to unintentional carbon monoxide poisoning.

Ford said it has high regard for the safety of its customers, and that its keyless ignition system is safe and reliable. The rest of the automakers have not given any comments yet.

General Motors recently recalled models of their Chevy Volt plug-in hybrid to install software that would automatically turn off the engine. The software will shut the car a few minutes after the fob is far from the car. There are other cars that make a horn sound to alert drivers not to leave their vehicles running.